Classification of Igneous Rocks

Dr. Ahmad Redaa

2024-09-25

Bases of Igneous Rock Classification

Issues with Terminology

Terms in Literature

The IUGS Classification

Plotting on a Triangular Diagram

Source: Winter, J. (2014)

Steps to Plot 70% X, 20% Y, and 10% Z

1. Understand the Axes of the Triangular Diagram

2. Plot the 70% X Value

3. Plot the 20% Y Value

4. Locate the Point

5. Verify the Z Value

Final Result

Classification Based on Mineral Content

Source: https://www.britannica.com

Classification of The Plutonic Igneous Rocks

Source: Winter, J. (2014)

Classification of Volcanic Rocks

Source: Winter, J. (2014)

Chemical Classification of Volcanic Rocks

Source: Winter, J. (2014)

Classification of Pyroclastic Rocks

Source: Winter, J. (2014)

Fragment Size Classification

Key IUGS Requirements

Types of Pyroclastic Rocks

Mixed Pyroclastic and Sedimentary Rocks

Special Types of Pyroclastic Deposits

Other Ignous Rocks

Source: Winter, J. (2014)